/*
 * Copyright 2020 by OLTPBenchmark Project
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 *
 */

package com.oltpbenchmark.distributions;

/**
 * An expression that generates a sequence of string values, following some distribution (Uniform,
 * Zipfian, Sequential, etc.)
 */
public abstract class Generator {
  /** Generate the next string in the distribution. */
  public abstract String nextString();

  /**
   * Return the previous string generated by the distribution; e.g., returned from the last
   * nextString() call. Calling lastString() should not advance the distribution or have any side
   * effects. If nextString() has not yet been called, lastString() should return something
   * reasonable.
   */
  public abstract String lastString();
}
